This application is based on and claims the benefit of German Application 199 31 404.7, filed Jul. 7, 1999, which is incorporated herein by reference.
The invention concerns a waveguide twist for connecting electromagnetic waveguides, comprising a torsion element with at least three individual parts lying side by side with no gap, which can rotate around the axis of the torsion element, in which each of the individual parts has a central passage hole with a cross-section which corresponds to the hollow cross-section of the waveguides, and in which the passage holes of the individual parts are aligned in a non-rotated condition of the torsion element (DE-C-3 733 397).
Such a waveguide twist can be used for connecting rectangular or elliptical waveguides. For the sake of simplicity, the rectangular cross-section below is considered representative also for the elliptical cross-section. Such a waveguide twist is needed, e.g., if a waveguide must be connected to another waveguide or connected with a device with a waveguide connection, and if the axes of the respective connection points are in planes twisted in relation to each other. A possible application area is, e.g., in antennas with parabolic reflectors and a feeder line formed by a rectangular waveguide. In such an arrangement, a continuing waveguide is connected to the feed line to establish the connection to a transmission and reception plant. Between the feed line and the continuing waveguide, a device can be connected which, by way of example, contains mixers or other electronic components. The polarization plane, in which the transmission electromagnetic waves fluctuate, is fixed through the rectangular waveguide of the feed line, and is set for the antenna through corresponding rotation or arrangement of the feed line in the reflector. The connection end of the feed line is set so that its rectangular opening can assume various positions. This can lead to difficulties if the position of the continuing waveguide, and, in particular the position of a device to be connected in between, is fixed as a result of which the positions of the connection openings of these components are also fixed. In this case, for the particular application, transition components must be employed which facilitate conduction of waves between the feed line and the components which are to be connected to it with as little loss as possible.
The waveguide twist according to the aforementioned DE-C-3 733 397 is composed, by way of example, of three waveguide sections which are connected to each other so as to be capable of being rotated with respect to each other around their long axes. In this way, the waveguide twist can be set to various angles between the axes of the open cross-section (i.e., the internal part of the waveguide which acts as a xe2x80x9cguidexe2x80x9d) at both of its ends. At the middle waveguide section, a lever is rotatably mounted externally which is oriented in a longitudinal direction of the waveguide twist. Projecting out at both ends of the lever are pegs which engage in channel grooves which are fabricated externally on the other two waveguide sections running in the longitudinal direction of the waveguide twist.
The construction of this known waveguide is expensive. With an increasing number of waveguide sections, it becomes increasingly complicated. The angle around which the waveguide sections can be rotated with respect to each other is limited by the fact that the pegs of the lever continue to engage in the channel grooves of the waveguide sections.
An object of the invention is to design more simply a waveguide twist of the type described above without limiting the angle of rotation.
This object is achieved according to the invention by a waveguide twist in which
a recess is formed in one face of each individual part the extension of which in circumferential direction corresponds to a specified angle of rotation;
pins oriented in an axial direction project from the other face of the individual parts, and
in the mounted position of the torsion element, a pin projecting from an individual part engages in the recess situated in the face of the adjacent individual part.
This waveguide twist is simple in construction and is easy to use, and no parts visible from the outside are used. Its angle of rotation is limited only by length of the recesses formed in the individual parts in circumferential direction. It is composed of a suitable number of individual parts of which the one, upon being turned, carries the adjacent part with it through the pin which engages in the corresponding recess. Upon a rotation of an individual part situated at the end of the torsion element around a specified angle of rotation, all of the other individual parts are thus carried with it and are rotated by the proper angle. For a given rotational angle of the waveguide twist, the greater the number of individual parts employed, the smaller the angles are around which the individual parts must be rotated. The electrical losses elicited by the torsion element become increasingly small with an increasing number of individual parts. The reflection factor of the same then becomes more favorable. The torsion element is advantageous not only upon initial construction of a waveguide arrangement but also if, by way of example, a different polarization plane must be set in an already installed antenna arrangement.